Propeller



July 1, 1936. E. G. MCCAULEY 1,769,81

PROPELLER Filed Nov. 15, 1924 Patented July 1, 1930 ERNEST e. monunnv, on DAYTQN, onro, ns'srenonfi'ro f. rnornnnnn CORPORATIOLLLA coaronnrronor r1:anvqszrivientnia-qa,

rnornnnnn Application filed-November 15,1924. serial No. 750,149 1. 5

'.This invention relates to propellers for air: craft generally, and has particular reference eliminating destructive v1-- to provisions for bration of the blades in operation.

The principal object of the invention con sists in providing wedgingmeans in the propeller hub serving to provide a solid or rigid hearing at the time the blade is assembled in the hub which will secure the blade tightely, and at the same time will not loosen up after the blade is in service, and enable destructive vibration. 3

Another object of the invention is to provide means in connection with the wedging means for loosening andwithdrawing the latter in the disassemblingof the propeller blades.

In the drawing illustrating my invention,

Fig. 1 is a central longitudinal section through thepropeller hub showing the improvements of my invention directed toward eliminating vibration.

Fig. 2 is a cross sectional detail on the line 22 of Fig. 1 looking in the direction indicated by the arrows. I Fig. 3 is a fragmentary sectional detai illustrating a modified form of wedgehaving means enabling the easy removal thereof from the propeller hub. Fig. 4 is a fragmentary sectional detail of a portion of a propeller hub of a slightly modified form utilizing a different form. of wedge operating after the fashion of the wedge shown in Fig. 3, but constructed of a] single piece instead of the two-piece Wedge appearing both in Figs. 1 and 3.

Fig. 5 is& cross sectional detail taken on theline 5-5 of 'Fig. 4 lookingin the direction of the small arrows. v

Throughout the figu'res'the same or similar reference numerals apply to corresponding parts.

The propeller hub comprises a pair of diametrically" opposed blade sockets 10,

formed preferably integral with a sleeve 11 fitting over and keyed upon the tapered end of the engine crankshaft 12. The sleeve 11 is secured to the shaft 12 by anut 13 thread ing on the end of the shaft 12, the nut. 13 being locked by a nut 14 threading in the outer end of the sleeve '11 and l orm indicated to. the nut 132 Any suitable of hub mounting may be utilized in connec tion with my invention. f Thesockets 1O constitute bladeholders for blades. 15 extending diametrically in opposite directions from. the propeller hub. The blades 15 are threaded at their innerIends as shown at 16 to thread into the internally threaded portion 17 at the inner ends of the socketslO. The "threads assume the thrust incident to centrifug'alaction in the operation of the propeller. Beyond the threaded portions 16 and the blades are provided with a solid or rigid 'bearing in the outer ends of the sockets 10 17 of the blades and sockets by two-piece cylindrical wedges 18. The t latter are cylindrical on their outer surfaces and have an outwardly tapering bore fitting the conversely taperedshanks 19 of the blades 15. The wedges 18 are backed up by gland nuts 20 threading on the outer ends ofthe sockets 10 as shown at 21., The wedges.

18-haveannular p the annular lips '23 of the gland nuts 20 to drive the wedges inwardly in the sockets. Where no wedges were provided and the ends rejections '22 engaged by' of the blades were cylindrical in form. and I .moved with an easy fit in the blade sockets.

to enable the threading'of the blades in'the up in the operation of the propeller-increased the tolerance, until the blade was free to vi brate considerably, so much so that, blades acter shown in my co-pending application above referred'to, the blades have a; solid bearing beyond thethreaded portions and 1n shown, or a wedging means of the char-1 sockets, it was found that the vibration set destructive vibration is eliminated. In the construction illustrated, the wedging means serves additionally to fasten-the blade in its adjusted position, so thatthe pitch will not vary in operation.

The wedges 18 are driven so tightly into the sockets'between the socket'wall and the, "blade that it becomeslalmost impossible to extract the same, when it is necessary to' remove. or adjust theblade. This is so, perioo i lus a ed a .wsdaal e 'a y t same form as t t. shown inE g'. l but providing in connection with the'annular projection 22 'reof, a gland nut having an outer annular lip23 and an inner annular lip 23'. On opposite sides of the annular pro ectig of the wed e into'the socket in the tightenof thejnut20', a d,the lip '23 serves to restricttlia wedge in t e loosening of the nut. The halves of the wedge are movable toward i at i the most reduced 'porti on' of the blade s ank, to'permit the entrance of, the annular projection 22 into the annulirgroove24between the lips 23 and 23?. Itiaobvious that'the loosen ng of the nut producesfthefloosening of the wedge so that an adjast ent .,qi the plate may be made; In caseit is desired to remove the late, the loosening of the nut'with the wedge is alternated withunthreading of the plate, until nut is entirely unthreaded, With the wedgeloosened the blade is free to be unthre'adedand reinoved from the socket.

In Fi and SI have illustrated a further m ificatio'n "wherein ablade'15 having a cylindrical shank 25 is received in a socket 10, the but'er end of which has its bore tapering inwardl "as shown at'26. A wedge 18' has acy'liii rical bore to fit the blade and is tapered on its. exterior to conform to. the tapering of the socket 10. The wedge 18' as shown in Fig. 5 is in one piece and splitlongitudinally as shown at 27, to permit the compression of the wedge to a smaller diameter so that the annular projection 22 at the outer end 'of the wedge may be engaged in the annular groove 24 of the gland nut 20'. So far as the operation of this wedge is concerned, it is similar to'the wedge 18 and is driven into the socket by the annular lip 23 in the tightening of the nut 20', and is loosened and withdrawn from the socket by the lip 23' in the loosening of the nut 20. The wedging action is secured in this case substantiall as in the instance above de scribed,and I, vided for the blade beyond the threaded inner end 16 thereof. The wedge, for easy entrance into the nut 20 has saw-cuts 28 p'referably at regularly spaced intervals in'the outer end of the wedge, to provide a plurality of tongues 29 of an odd number for a purpose resently to be described. The annular proection 22 is thusdivided into a plurality of lugs one for each tongue 29, so that the compression of the wedge to a smaller diameter 11 22 the lip 23 serves in the driving liquid state into the hole 32.

asolid or rigid bearing ispro'- is not tedious or impractical by having to compress a continuous annular projection.

ber of saw. cuts tovprovide an odd number of tongues 29,.t ere is avoidedthe likelihood of the wedge taking a set at the point diametrically opposite the slot 27 when they wedge is compressed, so the free ends thereof overlap as above described. After the compression of the wedge and its release, it

springs b'ack'to its normal size with the annular projection 22 entered in the annular groove 24 of the nut 20'. Since the wedge has a cylindrical bore it is free to pass over I the cylindrical end of the blade.

As is well understood 'n the art, the sockets and blades should be symmetrical as a slight diiierence in weight between the sevble to make the sockets and blades of exactly the same weight and hence rovision is made for increasing the weight 0 a socket or blade. A convenient means for Weightin one of the sockets and blades consists in rilling a hole 32 axially of the stem of the blade for the reception of a counterweight. The weight consists preferably of a plug of soft metal, as lead 33, which may be oured in a ome of the lead is then removed after it has solidified by a drill so that theblade may exactly balance a standard blade.

I claim: 7 i

1. In a propeller, a hub having a blade socket, a blade therefor, threaded portions on the blade end interfitting similar portions within said blade socket, wedge means intermediate the blade and blade socket to hold said blade against vibration and means asso- 'ciated with said first named meansfor increasing or decreasing the wedge action of fitting similar parts in the blade socket, means for securing said blade in said socket and means providing a wedgingaction to hold said blade in said socket when said securing means is tightened, said means constructed and arranged to provide a positive release in the loosening of said securin means.

3. In a propeller, the com ination with a hub having a blade socket, a blade therefor, threaded portions on the blade end interfitting similar portions within said blade socket, a wedge between said blade and blade ocket "and means for securing said blade in said socket, said means constructed andarranged to provide in tightening to drive the wedge tight and in loosening to loosen the wedge.

4. In a propeller, the combination with a hub having a blade socket of a blade therefor, threaded portions on the blade end interfitting similar portions within said socket, a nut threading on said socket and a wedge intermediate said blade and socket engaged by said nut in the tightening and loosening thGIIKGOf to move the wedge in and out of said soc et.

5. In a propeller, the combination with a I hub having a blade socket, a blade therefor, threaded portions on, the blade end int'erfitting similar portions within said blade socket, a member threadin on said socket a wedge member between said blade and said socket,

a groove in one of said members and a projection in the other of said members engaging in said groove whereby said wedge is moved in and out of said socket in the threading and unthreading of said member on said socket. 6. In a pro eller, the combination with a hub having a lade socket, ablade therefor,

threaded portions on the blade end interfitting similarportions within said blade socket, agland nut threading on said socket having an internal groove therein and a wedge between said blade and socket having a lug entering said groove.

7. In a propeller, the combination with a hub having a blade socket. a blade therefor, threaded portions on the blade end interfitting similar portions within said blade socket, a nut threadingon said socket and having an annular groove therein and a longitudinally split wedge adjacent said threaded portions on said blade end and intermediate said blade and blade socket, said wedge having an "annular projection to enter said annular groove in said nut whereby the overall diameter thereof may be reduced sufiiciently to enter the annular projection within said annular groove.

8. In a propeller, a hub having a blade socket, a blade therefor, threaded portions on the blade end interfitting similar portions within said blade socket, a nut threading on said socket and having an annular groove therein, a wedge about said blade and within said socket, said wedge being split longitudinally to permit its compression to a smaller diameter whereby to permit its entry within said nut and an annular projection on said wedge at the outer end thereof to enter said annular groove provided in said nut, said annular rojection terminating short of the longitudinal slot where said wed e is split to permit the overlapping of the rec ends of said wedge in compressing the same.

In testimony whereof I aflix my signature.

vllii bl'llg-l G. MGGAULEY. 

